Geography of Alabama

Physical Features.
The surface of Alabama in the N. and N.E., embracing about two-fifths of its area, is diversified and picturesque; the remaining portion is occupied by a gently undulating plain having a general incline south-westward toward the Mississippi and the Gulf. Extending entirely across the state of Alabama for about 20 m. S. of its N. boundary, and in the middle stretching 60 m. farther S., is the Cumberland Plateau, or Tennessee Valley region, broken into broad table-lands by the dissection of rivers. In the N. part of this plateau, W. of Jackson county, there are about 1000 sq. m. of level highlands from 700 to 800 ft. above the sea. South of these highlands, occupying a narrow strip on each side of the Tennessee river, is a country of gentle rolling lowlands varying in elevation from 500 to 800 ft. To the N.E. of these highlands and lowlands is a rugged section with steep mountain-sides, deep narrow coves and valleys, and flat mountain-tops. Its elevations range from 400 to 1800 ft. In the remainder of this region, the S. portion, the most prominent feature is Little Mountain, extending about 80 m. from E. to W. between two valleys, and Asing precipitouslyon the N. side 500 ft. above them or 1000ft. above the sea. Adjoining the Cumberland Plateau region on the S.E. is the Appalachian Valley (locally known as Coosa Valley) region, which is the S. extremity of the great Appalachian Mountain system, and occupies an area within the state of about 8000 sq. m. This is a limestone belt with parallel hard rock ridges left standing by erosion to form mountains. Although the general direction of the mountains, ridges and valleys is N.E. and S.W., irregularity is one of the most prominent characteristics. In the N.E. are several flat-topped mountains, of which Raccoon and Lookout are the most prominent, having a maximum elevation near the Georgia line of little more than 1800 ft. and gradually decreasing in height toward the S.W., where Sand Mountain is a continuation of Raccoon. South of these the mountains are marked by steep N.W. sides, sharp crests and gently sloping S.E. sides. South-east of the Appalachian Valley region, the Piedmont Plateau also crosses the Alabama border from the N.E. and occupies a small triangular-shaped section of which Randolph and Clay counties, together with the N. part of Tallapoosa and Chambers, form the principal portion. Its surface is gently undulating and has an elevation of about 1000 ft. above the sea. The Piedmont Plateau is a lowland worn down by erosion on hard crystalline rocks, then uplifted to form a plateau. The remainder of the state is occupied by the coastal plain. This is crossed by foot-hills and rolling prairies in the central part of the state, where it has a mean elevation of about 600 ft., becomes lower and more level toward the S.W., and in the extreme S. is flat and but slightly elevated above the sea. The Cumberland Plateau region is drained to the W.N.W. by the Tennessee river and its tributaries; all other parts of the state are drained to the S.W. In the Appalachian Valley region the Coosa is the principal river; and in the Piedmont Plateau, the Tallapoosa. In the Coastal Plain are the Tombigbee in the W., the Alabama (formed by the Coosa and Tallapoosa) in the W. central, and in the E. the Chattahoochee, which forms almost half of the Georgia boundary. The Tombigbee and Alabama unite near the S.W. corner of the state, their waters discharging into Mobile Bay by the Mobile and Tensas rivers. The Black Warrior is a considerable stream which joins the Tombigbee from the E. The valleys in the N. and N.E. are usually deep and narrow, but in the Coastal Plain they are broad and in most cases rise in three successive terraces above the stream. The harbour of Mobile was formed by the drowning of the lower part of the valley of the Alabama and Tombigbee rivers as a result of the sinking of the land here, such sinking having occurred on other parts of the Gulf coast.

The fauna and flora of Alabama are similar to those of the Gulf states in general and have no distinctive characteristics.

Climate and Soil.
The climate of Alabama is temperate and fairly uniform. The heat of summer is tempered in the S. by the winds from the Gulf of Mexico, and in the N. by the elevation above the sea. The average annual temperature is highest in the S.W. along the coast, and lowest in the N.E. among the highlands. Thus at Mobile the annual mean is 67 degrees F., the mean for the summer 81 degrees, and for the winter 52 degrees ; and at Valley Head, in De Kalb county, the annual mean is 59 degrees, the mean for the summer 75 degrees, and for the winter 41 degrees . At Montgomery, in the central region, the average annual temperature is 66 degrees, with a winter average of 49 degrees, and a summer average of 81 degrees . The average winter minimum for the entire state is 35 degrees, and there is an average of 35 days in each year in which the thermometer falls below the freezing-point. At extremely rare intervals the thermometer has fallen below zero, as was the case in the remarkable cold wave of the 12th-13th of February 1899, when an absolute minimum of 17 degrees was registered at Valley Head. The highest temperature ever recorded was 109 degrees in Talladega county in 1902. The amount of precipitation is greatest along the coast (62 in.) and evenly distributed through the rest of the state (about 52 in.). During each winter there is usually one fall of snow in the S. and two in the N.; but the snow quickly disappears, and sometimes, during' an entire winter, the ground is not covered with snow. Hail-storms occur in the spring and summer, but are seldom destructive. Heavy fogs are rare, and are confined chiefly to the coast. Thunderstorms occur throughout the year, but are most common in the summer. The prevailing winds are from the S. As regards its soil, Alabama may be divided into four regions. Extending from the Gulf northward for one hundred and fifty miles is the outer belt of the Coastal Plain, also called the ``Timber Belt, whose soil is sandy and poor, but responds well to fertilization. North of this is the inner lowland of the Coastal Plain, or the ``Black Prairie, which includes some 13,000 sq. m. and seventeen counties. It receives its name from its soil (weathered from the weak underlying limestone), which is black in colour, almost destitute of sand and loam, and rich in limestone and marl formations, especially adapted to the production of cotton; hence the region is also called the ``Cotton Belt. Between the ``Cotton Belt and the Tennessee Valley is the mineral region, the ``Old Land area---``a region of resistant rocks--whose soils, also derived from weathering in silu, are of varied fertility, the best coming from the granites, sandstones and limestones, the poorest from the gneisses, schists and slates. North of the mineral region is the ``Cereal Belt, embracing the Tennessee Valley and the counties beyond, whose richest soils are the red clays and dark loams of the river valley; north of which are less fertile soils, produced by siliceous and sandstone formations.

Related topics

• Alabama
• Geography of the United States

External links

• State of Alabama Geological Survey (http://www.gsa.state.al.us/)
• USGS - Tapestry of Time - Alabama (http://tapestry.usgs.gov/states/alabama)